PT13 Aquatic Ecotoxicology I
Exhibit Hall
8:00 AM - Tuesday
(PT181) Influence of Sediment Organic Carbon and Clay Content on the Bioavailability of Hexachlorobenzene.
Henry, K1, Qiu, X1, Saghir, S1, Davis, J1, Woodburn, K1, 1 The Dow Chemical Company, Midland, MI, USA
ABSTRACT- The purpose of this study was to assess the effects of varying sediment organic carbon, and clay contents and type on the bioavailability of hexachlorobenzene to the freshwater oligochaete, Lumbriculus variegatus and to rats. Formulated sediments adapted from the standard OECD artificial soil matrix were prepared using various ratios of kaolin clay, montmorillonite clay, sand, peat moss, and soot carbon, and were spiked with 14C-radiolabeled hexachlorobenzene. The worms were exposed to these sediments at the time of HCB amendment. Male Fischer 344 rats were exposed to similarly prepared sediments via oral gavage. In parallel to the bioavailability studies, another study is being conducted to examine the effects of aging on the multiphasic desorption kinetics of 14C-HCB. Preliminary results from the rat oral dosing studies indicate that the organic carbon and clay content may not strongly influence the bioavailability of HCB in freshly prepared artificial sediments. In future studies, absolute oral bioavailability of HCB in rats will be determined by comparing the area under the blood concentration curves (AUC) of oral and intravenous dosing. Confirmation of the results is also being examined in the freshwater oligochaetes.
Key words: sediment, bioavailability, hexachlorobenzene, Lumbriculus variegatus